Periferal ulnar nerve compression in the ulnar tunnel of the wrist (Guyon’s canal) is a seldom occurring neurological condition with a musculoskeletal background. The purpose of this article is to discuss the detailed anatomy of the ulnar tunnel (with respect to the motor and sensitive branches of the ulnar nerve and including topographic magnetic resonance images of the tunnel) and to remind of the numerous possible causes of this problem. Review of the literature is given and is followed by the presentation of findings in our own cases. Finally, pathological findings in the surrounding structures, which might mimick this condition, will provide an interesting differential diagnosis.

        Key words: ulnar nerve – Guyon’s canal – nerve compression